Abstract: An optical scanning system in which light emitted from a light source is deflected by a deflector and converged onto a surface to be scanned by an optical image forming system. The optical image forming system has a curvature of field in a sub-scanning direction to cancel a change in a beam spot diameter caused by a change in an F-number in the sub-scanning direction, depending on an image height in the main scanning direction. The invention is also addressed to a method for determining a curvature of field in the optical scanning system.

Abstract: Disclosed is a slide-in formatter which can be installed in an image forming device such as a laser printer or a fax machine. The image forming device is fitted with a card cage on an interior side of the device housing. A formatter receiving slot is formed in the housing, adjacent to the card cage, extending from the exterior of the housing to its interior. The card cage includes a pair of opposing receiving rails positioned to receive and hold the side edges of formatter board. Suitable mating electrical connectors are attached to both the slide-in formatter board and the card cage which will complete an electrical connection between the slide-in formatter and the internal components of the image forming device.

Abstract: The present invention provides a method of ameliorating the effects of misalignment between modulator, and a system using the same. The individual modulator elements are positioned such that a portion of the image produced is generated by both elements. The contribution to the combined output made by each element varies across the overlapped region, with each element making a small contribution to the pixels in the overlapped region at one end and a large contribution to pixels in the overlapped region at the other end. Because the overlapping output regions of the modulators collectively form a portion of the image, any alignment error is effectively spread over the entire overlapped region and is much less noticeable.

Abstract: Apparatus for estimating LED printhead junction temperature as a function of an input data stream, and for automatically compensating the printhead drive signal to maintain proper printer calibration to provide junction-level compensation for efficiency loss of an LED as the LED warms due to thermal energy generation from an electrical drive current is effected by a plurality of selectable LED temperature-specific look up tables constructed for a plurality of different LED temperatures. The selected look up table produces an output for driving the LED when the selected look up table is accessed by the input data. A model of the thermal characteristics of the LED, its heat sink, and the structure attaching the LED to the heat sink is adapted to produce an estimate of the temperature of the LED as a function of the image data. An address decoder selects one of the plurality of look up tables to process the input data stream in accordance with the estimate produced by the model.

Abstract: In a printing station, pins for engaging edge perforations of the paper are mounted on a toothed belt. The paper is lifted from a position fully engaged on the pins to a tapered head portion of the pins higher up on the pins to avoid stress on the paper from the pins. Lifting of the paper is provided by a paper guide element.

Abstract: A device for producing a screen printing stencil has a light source for emitting a bundle of light whose focus lies in the region of a light-sensitive layer present on a stencil screen. Furthermore, there is an apparatus for generating a relative movement between the bundle of light being incident on the light-sensitive layer in accordance with a desired stencil pattern. The bundle of light is linearly polarized in at least one section. An electro-optical modulator for rotating the plane of oscillation of the bundle of light is arranged in this section. The electro-optical modulator rotates the plane of oscillation of the bundle of light in accordance with received stencil pattern data. An analyzer is positioned in the light path downstream of the electron optical modulator. The analyzer passes the bundle of light having a plane of oscillation at one orientation and blocks the bundle of light having a plane of oscillation at an opposite orientation.

Abstract: A holder (10) for refilling an ink jet printhead (11) comprises a box (21) and two covers (22, 23), pivoted upwardly on the box (21) for being rotatable reciprocally and with respect to the box (21). A first cover (22) is provided for positioning and locking the printhead (11) into the box (21). A second cover (23) is superimposable to the first cover (22) and is provided with a seat (30) for being coupled with a refill cartridge (34) so as to refill the printhead (11). A short tube (31) is mounted in the second cover (23) inside the seat (30) to allow ink to pass from the cartridge (34) to the printhead (11) for refilling the latter. Pivoting of the two covers (22 and 23) allows simple and exact positioning of the same covers with respect to the printhead (11), first to lock it into the box (21) and then to fill the printhead (11) with ink.

Abstract: An image forming apparatus such as an electrophotographic type printer or a facsimile includes a laser diode and a photosensitive drum. A plurality of selective driving circuits are provided for driving the laser diode, and at least one of the driving circuits is selected to form dot images having variable sizes on the photosensitive drum in accordance with a given data supplied by a computer. The driving circuits have different driving currents, and a smaller dot image is formed when a driving circuit providing a lower driving current is selected. Also, delay elements are provided to form a dot image at a delayed timing. The apparatus also has a smoothing function to correct jaggies in a picture.

Abstract: An apparatus for generating a laser beam modulated on the basis of an information signal, which comprises a circuit for generating a first information signal, a circuit for generating a second information signal, independent of the first information signal, a circuit for driving a semiconductor laser on the basis of the first and the second information signals, wherein the driving circuit comprises first and second switching elements which operate supplementarily with each other, one of the first and second switching elements switches a drive current to the semiconductor laser, and wherein the first information signal is provided into a control terminal of the first switching element and the second information signal is provided into a control terminal of the second switching element.

Abstract: Compensation for pixel aberrations in a laser printer is accomplished by altering pixels in accordance with pixel location. A projection of a scan line is skewed with respect to a line normal to the surface of an optical photoreceptor (OPR), which results in a change in the shape of projected pixels. Selected pixels are augmented in order to adjust their shape. The additional optical energy may be applied at the sub-pixel level so that a threshold of energy depletion on an optical photoreceptor (OPR) is not reached where image development would occur. Alternatively, the additional energy may be applied in a manner which provides additional development to simulate a pixel having a desired width across a scan line. The invention allows a scan line to be produced in which pixels across the scan line are made more uniform.

Abstract: An optical scanning apparatus has a light source, a first optical system for converting luminous flux emitted from the light source to converged luminous flux, a deflector for deflecting the converged luminous flux emitted from the first optical system, and a second optical system for forming an image in a spot shape on the plane to be scanned from luminous flux deflected by the deflector. The second optical system comprises a single lens. Parameters R.sub.1, R.sub.2, Y.sub.max, S.sub.1, S.sub.2, and d of the single lens satisfy the following expressions, with R.sub.1 denoting the paraxial curvature radius of the lens surface facing the deflector in the single lens, R.sub.2 denoting the paraxial curvature radius of the lens surface facing the plane to be scanned in the single lens, Y.sub.max denoting the maximum effective diameter on the main scanning plane of the single lens, S.sub.

Abstract: The present invention relates to a method for improving the print quality of an image recording apparatus in which charged particles are transported from a particle source and deposited in an image configuration on an information carrier. Variable control voltages are supplied to control electrodes to permit or restrict the transport of charged particles from the particle source during a predetermined print time. The control voltage levels, the print time length or the voltage levels and the print time length are dimensioned in relation to the specific distance between each control electrode and the particle source. The present invention relates also to a device for accomplishing the method.

Abstract: The present invention provides an optical exposer unit having a large space for containing black toner, and a color image forming apparatus comprising the optical exposer unit. In an optical exposer unit, first and second laser beams, which are reflected on the respective reflection surfaces of a polygonal mirror unit and passed in a direction farther from a photosensitive drum than an optical axis of an optical system including first to third image-forming lenses, are reflected on second mirrors, and mutually crossed each other so as to be guided to the photosensitive drum corresponding to third mirrors. Thereby, a sufficient space is provided to the surroundings of a black image forming section. Therefore, the space for containing black toner can be largely ensured as compared with the space for containing the other color toner.

Abstract: A photoplotting apparatus is provided. The apparatus comprises an internal drum plotter and a media sheet handling apparatus for sequentially delivering a photosensitive media sheet to the photoplotter for exposure from a stack of such sheets. The photoplotter has reduced turbulence within the drum during exposure of the media sheet, and the sheet handling apparatus includes means for separating the sheets in the stack from interleaves disposed between adjacent sheets in the stack.

Abstract: An apparatus has a plurality of semiconductor cells as current switchings for driving a laser diode which exposes to light a photosensitive member so as to effect image recording. The semiconductor cells have each different characteristics, or same characteristics respectively. In response to the light amount signal corresponding to light quantity of the laser diode, a selector selects one or more of the semiconductor cells so as to supply a suitable driving current turned on or off later with an image signal. As a result, no fluctuations in the pulse duty ratio and the rise time are present in the entire driving current active range, thus improving the quality of a recorded image. The effect of selection by the selector is held for a certain recording time, whereby malfunction due to noises or the like can be avoided, and stable actions of the laser diode are ensured.

Abstract: A laser recording apparatus with a laser recording unit which is movable while held horizontal at all times. The laser recording apparatus is constructed of a first frame including the bottom section of the apparatus and a second frame supported by the first frame in a manner which allows pivotable rotation of the second frame for opening the apparatus, wherein a laser recording unit including laser scanning means is supported by the second frame on the rotation fulcrum, and the laser scanning means is held horizontal to the bottom section of the apparatus before, during and after release of the second frame from the first frame.

Abstract: An imaging system for forming multiple superimposed image exposure frames on a photoconductive member moving in a process direction including a rotating polygon having a plurality of facets. A raster output scanner forms a plurality of scanlines in a transverse direction across the photoconductive member by reflecting modulated beams from the rotating polygon. A method of providing scanning speed and phase shift control by providing a signal representing image exposure frame registration and a start of scan (SOS) signal representing the beginning of a scanline. The relative phase between the start of scan signal and the signal representing image exposure frame registration is determined and converted into a digital signal along with a speed determination signal by use of a fast clock timer. The digital signals are summed and inverted in polarity in order to change the speed of the rotating polygon to synchronize the signal representing image exposure frame registration with the SOS signal.

Abstract: An image forming apparatus has four color image forming and transferring portions and four image writing heads supported by a cover to be rotatably movable upwardly and downwardly. Each case of the portions is so shaped that it does not interfere with the rotational movement of the heads, and has the same shape. Particularly, two opposite side surfaces of the case is so shaped that it does not project into the movement locuses of the heads not to collide them.

Abstract: An image recording apparatus of the present invention comprises: an image processing means for compensating the color and gradation of an inputted color image; a monochromatic CRT; a display means for successively inputting color images, having a plurality of colors, into the monochromatic CRT, and for displaying a plurality of images on the monochromatic CRT as monochromatic images; an optical system for forming the monochromatic image, displayed on the monochromatic CRT, onto a color photographic paper; a plurality of color filters, which are selectively inserted between the monochromatic CRT and the color photographic paper, and convert the monochromatic image into a plurality of monochromatic color images; an exposure luminance setting means for each separation color; and an emitting luminance control means.

Abstract: A multi-beam optical system includes: a light beam generating part for generating a plurality of light beams using a plurality of light-emitting parts which are offset from each other in the sub-scanning direction and which are individually controllable; a coupling optical part for transmitting said plurality of light beams generated by said light beam generating part; an aperture part for defining said plurality of light beams, respectively; a beam combiner part for combining said plurality of light beams; a first image forming part for forming images of said plurality of light beams passing through said coupling optical part; a deflector part for deflecting said plurality of light beams output from said first image forming part, the images of said plurality of light beams being formed in a vicinity of said deflector part; and a second image forming part for forming images of said plurality of light beams deflected by said deflector part, wherein an exit pupil is in a conjugated arrangement with said second